Process for resolving petroleum emulsions



Patented Dec. 24, 1940 PROCESS FOR RESOLVING PETROLEUM EMULSIONS Melvin De Groote, UniversityCity, Mo., assignor to Petrolite Corporation, Ltd., Wilmington, Del'., a corporation of Delaware I No Drawing. Original application May 12, 1939,

Serial No. 273,222. Divided and this application ctober23, 1939, Serial No. 300,844

4 Claims. (01. 252-334) This invention relatesprimarily to the treatment of emulsions of mineral oil and water, such as petroleum emulsions, for the purpose of separating the oil from the water, the present ap- 5 plication being a division of my pending application Serial No. 273,222, filed May 12, 1939.

I The object of my invention is to provide a novel .process for resolving petroleum emulsions of the water-in-oil type, that are commonly referred to as cut oil, roily oil, "emulsified oil, etc.,

and which comprise fine droplets of naturallyoccurring waters or brines dispersed in a more or less permanent state ,throughout the oil which constitutes thecontinuous phase of the emulsion.

Briefly described, my process consists insubjecting an emulsio'nof the kind mentioned to the action of atreatingagent or demulsifier consisting of a certain kind of amine salt derived from water-soluble petroleum sulfonic acid or acids of the kind hereinafter described.

Petroleum sulfonic acids are produced from a wide variety of petroleum distillates or petroleum fractions, and in some instances, they are produced from the crude petroleum itself. When produced from crude petroleum itself, it is customary to use crude oil of the naphthene type, crude oil of the paraflin type, crude oil of the asphaltic type, and mixtures of said three different types of crude oil} 39 The art of refining petroleum crude or various fractions, using sulfuric acid of various strengths, as well as monohydrate and fuming acid, is a well known procedure. In such conventional refining procedure, petroleum sulfonic acids have 35 been produced as by-products. For instance, in removing the olefinic components, it has been common practice to use sulfuric acid, so as to polymerize the olefines or convert them into sulfonic acids, which are subsequently removed. 40 Likewise, in the production of white oil or highly refined lubricating oils,it has been customary to treat with fuming sulfuric acid, so as to eliminate certain undesirable components.

In recent years, certain mineral oil fractions 4 have been treated with sulfuric acid with the primary object of producing petroleum sulfonic acids, and in such procedure the petroleum'sulfonic acids represented the primary objects of reaction, rather than concomitant by-products. 50 Petroleum sulfonic acid, regardless of whether derived as the principal product of reaction or as a by-product, can be divided into two general types, to wit, green-acid or acids and mahogany acid or acids. The green acids are characterized by being water-soluble or dispersible. In other words, they form either true solutions or sols. For purpose of convenience, they will be herein referred to as water-soluble, without any effort to indicate whether the solution is molecular or colloidal in nature. The green acids, as indi- 5 cated by their name, frequently give an aqueous solution having a dark green or grey-green appearance. They generally appear as a component of the acid draw-off, and do not remain behind dissolved in the oil fraction which has 10 been subjected to sulfuric acid treatment. The green acids are not soluble in oil, even when substantially anhydrous, and certainly are not soluble in oil when they contain as much as 15% of water. Similarly, their salts obtained by neul5 tralization with a strong solution of caustic soda, caustic potash, or ammonia, are not oil-soluble. For convenience of classification, the ammonium salt will be considered as an alkali salt.

In contradistinction to the hydrophile green 20 acids, there occurs, as in the manufacture of medicinal white oil, the oil-soluble type or the mahogany acids. These mahogany acids are characterized by being soluble in oil, especially when anhydrous, and being soluble in oil, even if they contain some dissolved water. Some of the mahogany acids also show limited hydrophilic properties to the extent that either some water can be dissolved in the acids, or they, in turn, may dissolve to some extent in water. In, some instances their salts, such as the sodium, ammonium, or potassium salt, will dissolve in water to give a colloidal sol. However, regardless of the presence of any hydrophilic properties whatsoever, they always have a characteristic hydrophobe property, as indicated by the fact that the substantially anhydrous form, for instance, their alkali salts containing 5-12% water, will dissolve in oil. This clearly distinguishes them from the green acids previously.referred to, because the green acids in similar form containing the same amount of water, for example, will not dissolve in oil. The green acids, as such, are essentially hydrophilic and non-hydrophobic in character.

The utility of the mahogany acids in various arts has been enhanced by increasing their water solubility; for instance, converting the mahogany acids into hydroxy alkyl-amine salts. 0n the other hand, as far as I am aware, no valuable product of commerce has resulted from F decreasing the water solubility of the mahogany acids by the addition of some oil-soluble basic amine, such, for example, as triamylamine.- The triamylamine salts of mahogany acids, for example, are completely devoid of any solubility in water which the alkali salts may have exhibited and show, as would be expected, an increased solubility in hydrophobe solvents.

Green acids are hydrophile in character, as previously stated. Their hydrophile character has been increased by neutralization with material such as triethanolamine and the like. Such green acid salts having enhanced water solubility as compared with the ordinary alkali salts, have found application in certain arts.

I have found that when green acids, 1. e., the oil-insoluble type, are neutralized with a substituted aldimine, as hereinafter described, so as to produce a water-insoluble product that the resulting material, even though it does not exhibit any marked oil solubility, especially when it contains 5-10% of water, still has pronounced value as a demulsifier for oil field emulsions, either when used alone, or in conjunction with other known demulsifying agents. I employ a substituted aldimine of the kind derivable most readily by reactions involving an aldehyde and an amine other than an arylamine. Details as to the manufacture and nature of such bases are hereinafter described. I have also found that such substituted aldimine salts of green acids will mix in with a hydrophobe material and a hydrophile material, so as to produce a homogeneous mixture. The effectiveness of the above described material or composition of matter as a demulsifying agent for oil field emulsions appears to be related to some factors other than its solubility characteristics.

The new composition of matter that is employed as the demulsifler in my process is represented by substituted aldimine salts of hyprophilic, non-hydrophobic green petroleum acids, as exemplified by the salt derived from such green acids by neutralization with a base obtained by reaction between a mole of octylamine and a mole of acetaldehyde. The manufacture of said composition of matter involves nothing more or less than neutralizing one molecule of the selected petroleum acid with one molecule of a suitable 5 base until neutral to methyl orange indicator or other suitable indicators. For purposes of convenience, I prefer that the selected petroleum sulfonic acid contain not over 15% of water. It is understood, of course, that the conventional procedure in employing double decomposition, instead of direct neutralization can be utilized in the manufacture of my new material or composition of matter. For instance, the sodium salt of the selected petroleum suli'onic acid can be dissolved in alcohol or other suitable solvent, and the base hydrochloride added so that sodium chloride will precipitate. After filtering off the precipitated sodium chloride, the alcohol can be evaporated and the petroleum sulfonic acid salt recovered.

It so happens that the commonest example of a substituted aldimine represents a type of material not employed in the present instance. Reference is made to the type of material frequently known as a Schiffs base, and sometimes, in order to emphasize its aromatic character, as an anil. Such materials are obtained by reactions between an arylamine and an aldehyde, which may or may not be aromatic in nature. Reference is made to the following statement, which is found in Textbook of Organic Chemistry, by Richter, 1938, page 502:

The reaction of primary aryl amines and aldehydes leads to a type compound referred to as a Schifls base or azomethine, substances which contain the structure CH=N-. Acetalde'hyde and aniline react to form ethylidine aniline.

If an aldehyde, for instance, acetaldehyde, is converted into the imide, i. e., the aldo-imide, sometimes known as the aldo-imine, or aldimine, then the transformation may be indicated in the following manner:

om=o oH=o=Nn Obviously, if the imino hydrogen atom is replaced by a suitable substituent, for instance, a alkyl radical, an aralkyl radical, or an alicyclic radical, then one obtains a compound indicated by the following formula:

11 BC=NT in which T represents a non-aryl monovalent hydrocarbon radical of the kind just described; and in the case of a Schifi's base, or an anil, the composition is similar, except that T represents an aryl residue. Obviously, one need not depend on reactions involving formaldehyde, for instance, or acetaldehyde; but one may employ aldehydes of higher molecular weight, such as heptaldehyde, octaldehyde, lauric aldehyde, palmitic aldehyde, hexahydro benzaldehyde, phenyl acetaldehyde, and stearic aldehyde, etc. As a matter of fact, when aldehydes of low molecular weight are employed, there is a greater tendency to obtain reactions other than the desired substituted aldimine. Note, for instance, the following statement found in Richters Organic Chemistry, Allott, volume 1, third (1934) edition, page 250: Q

"By the use of aldehydes of higher molecular weight, the tendency to polymerization on the part of the reaction products of primary amines and aldehydes diminishes and Schiifs bases are formed.

"Methylisobutylideneamine,

(CH3)2CH.CH=N.CH3, b. p. 68.

Note in this instance the term "Schiifs base is not limited to aromatic materials such an anils, but-is extended to non-aryl compounds.

Commercially, heptaldehyde is most readily available, in view of its manufacture, by the distillation of castor oil. My preference is to react heptaldehyde with octylamine, so as to obtain the corresponding octyl aldimine.

In the manufacture of such compounds, any suitable non-aryl primary amine can be employed, but I have found, by experience, that generally speaking, it' is most desirable to use the most readily available amine, such as monoamylamine, monocyclohexylamine, benzylamine, or octylamine. Amines of higher molecular weight, such as oleylamine, may be employed. Instead of cyclohexylamine, one may, of course, employ homologues obtained by the hydrogenation of methyl aniline or the like, instead of by the hydrogenation of aniline. Similarly, benzylamine may be looked upon as a derivative of benzyl alcohol, and one may accordingly'us'e otherhomologues derived from homologues of benzyl alcohol. A wide variety of alkylamines, of course, are available; and those employed may contain-a hydroxy radical, such as monobutanolamine, monopentanolamine, monoethanolamine, hydroxyether amine (OHC2H4OC2H4NH2), and the like. My preference, however, is to use non-hydroxylated 50 sation. For this reason, in most instances, if it non-aryl amines. Hexadecylamine and octadecylamine may be employed. j

An aromatic aldehyde, such as benzaldehyde, may be employed; unsaturated aldehydes, such as acrolein, crotonaldehyde, or tiglic aldehyde, may be employed, but. are objectionable, due to the fact that they enter into an entirely different series of reactions with primary amines. Heterocyclic aldehydes, such as furfuraldehyde,

. may be employed. Similarly, one may employ hydroxy aldehydes, such as aldol; but here again, the use of such a substituted aldehyde is objectionable, in that another series of undesirable reactions may take place. My preference is to employ an unsubstituted aldehyde having at 'least five carbon atoms and not more than 8 carbon atoms, such as furfural, benzaldehyde, or heptaldehyde, and further characterized by freedom from an unsaturated aliphatic group. One may also employ an aralkyl aldehyde, such as phenylacetaldehyde, CcI-I5.CH2.CHO, or an alicyclic aldehyde, such as hexahydro-benza-ldehyde.

If an aldehyde is employed in which an alcoholic hydroxyl radical is present, then either prior to or after the formation of the aldimine, the hydroxyl radical may be removed, if desired, by an acylation reaction involving a member of the lower fatty acid series, such as acetic acid, butyric acid, heptoic acid, or the like, having seven carbon atoms or less; .or by an acid having at least 8 carbon atoms and not more than 32 carbon atoms, and of the kind referred to as a detergent-forming acid, such as a fatty acid, in-

cluding oleic acid, stearic acid, and the like;

ora petroleum acid, such as a naph-thenic acid, oraresin acid, such as abietic acid. In such acylation reactions, instead of employing the acid,one-, may employ any suitable compound, such as the acyl chloride, anhydride, etc. Similarly, one may acylate the hydroxyl radical or radicals attached to an amine, as in the case of ethanolamine or glycerylamine. In such acylation reactions, precautions must betaken to prevent any undesirable side reactions; as, for instance, if monopropanolamine is esterified with an acid, the formation of a substituted amide or an imide must be prevented. Similar diiiicul'ties may arise in the acylation of a material such as aldol, as, for example, a condensation of the type commonly known as an aldol condenis deemed undesirable to remove an alcohollform hydroxyl from the substituted aldimine, such hydroxyl should be removed after the substituted aldimine has been formed,

" The "substituted aldimine employed in the present process may be characterized by the formula:

in which B is a hydrogen atom or a residue derived from an aldehyde and may be alkyl, aralkyl, aryl, alicyclic, or heterocyclic in nature; and T is a residue derived from a primary amine and may be alkyl, aralkyl, or alicyclic in nature, or hydroxylated derivatives of these three types,

, or acylation compounds derived from acids or their functional equivalents, and such hydroxy hydrocarbon radicals.

In practising my process I prefer to use a demulsifier that is manufactured in the manner which has already been suggested in consideraoctylamine, so as to produce the corresponding octyl aldimine; or, for the sake of convenience, will be indicated as octyl heptaldimine.

The reaction takes place very readily at ordinary temperature, and sometimes must be retarded by means of a cooling agency during the early stages of the reaction. During the latter stages of the reaction, moderate heat may be employed to insure completion. If desired, conventional procedures may be employed to eliminate unreacted aldehyde or unreacted amine. However, if the reaction is conducted carefully, a substantial and generous yield of the desired aldimine is obtained, and it is unnecessary to resort to any purification. It has been previously pointed out that having obtained an amine of the kind desired, it is only necessary to proceed to neutralize the green acid, as previously indicated.

Obviously, as to the preparation of the preferred reagent, no additional information is required. However, it may be well to point out that I prefer to use a green acid selected so that it is relatively free from inorganic acids, such as sulfurous acid and sulfuric acid, and containing not over 15% water, and preferably as little unsulfonated-hydrocarbon material as possible.

these petroleum sulfonic acids may carry some polymerized oleflnes, free hydrocarbons, or the like, or may even carry a bit of naphthenic acids which represent carboxylated non-sulfonated petroleum acids. As previously stated, these materials are well known commercial products and are available in the open market either in the form of the acid itself, or in the form of a. salt.

In the claims the aldimine isreferred to as basic, to indicate that the basicity is in the neighborhood of that of ammonia, triethanolamine, or

amylamine. In some cases the basicity may be.

somewhat greater, in fact, perhaps considerably greater, and in some instances, slightly less. In order to insure such asicity, it is necessary that there be no aryl or aromatic radical attached to the amino nitrogen atom from which the sub-. stituted aldimine is produced. In other words, such materials as aniline, naphthylamine, etc., are not satisfactory, due to the presence of an aryl radical attached indirectly to the amino nitrogen atom. The substituted aldimines derived from such aromatic bases result in the formation of Schifis bases, previously described, which are of such low basicity that they do not form stable salts with the petroleum acids of the kind described. For this reason, the expression basic non-aryl is employed to clearly characterize the substituted aldimine. The term s fonic acid usedin the claims, is intended to refer to a substance consisting either of a single acid or a mixture of acids.

The new process that I have devised for resolving or breaking petroleum emulsions of the water-in-oil type involves subjecting the emul-' sion to the action of a demulsifier consisting of the above described new material or composition of matter. Said material is used either alone, or in admixture with another or with other conventional demulsifying agents, and its method of use is the same as that generally employed in resolving or breaking petroleum emulsions of the water-in-oil type with a chemical demulsifier. Briefly stated, the conventional method of using a chemical demulsifier to break a petroleum emulsion consists in introducing the demulsifier into the well in which the emulsion is produced; introducing the demulsifier into a conduit through which the emulsion is flowing; or introducing the demulsifier into a tank in which the emulsion is stored. After treatment the emulsion is allowed to stand in a quiescent state, usually in a settling tank and usually at a temperature varying from atmospheric temperature to about 200 F., so as to permit the water or brine to separate from the oil, it being preferable to keep the temperature low enough to prevent the volatilization of valuable constituents of the oil. The amount of demulsifier that may be required to break the emulsion may vary from 1 part of demulsifier to 500 parts of emulsion, up to 1 part of demulsifier to 20,000, or even 30,000 parts of emulsion.

I desire to point out that the superiority of the reagent or demulsifying agent contemplated in my process is based upon its ability to treat certain emulsions more advantageously and at a somewhat lower cost than is possible with other available demulsifiers, or conventional mixtures thereof It is believed that the particular demulsifying agent or treating agent herein described will find comparatively limited application, so far as the majority of oil field emulsions are concerned; but I have found that such a demulsifying agent has commercial value, as it will economically break or resolve oil field emulsions in a number of cases which cannot be treated as easily or at so low a cost with the demulsifying agents heretofore available.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A process for resolving petroleum emulsions of the water-in-o1l type, characterized by subjecting the emulsion to the .action of a demulsifier, comprising a water-insoluble salt of a basic substituted aldimine of the formula type:

B B('J=NT in which B is selected from the class consisting of hydrogen atoms, hydroigy hydrocarbon and hydrocarbon radicals, and T is selected from a non-aryl class consisting of hydrocarbon radicals, hydrocarbon radicals interrupted at least once by an oxygen atom, hydroxy hydrocarbon radicals, and radicals obtained by the acylation of a hydroxy hydrocarbon radical, in which the acylating compound is derived from an acid containing not more than 32 carbon atoms; said aldimine salt being obtained from water-soluble, non-hydrophobe petroleum sulfonic acid of the green acid type.

2. A process for resolving petroleum emulsions of the water-in-oil type. characterized by subjecting the emulsion to the action of a demulsifier, comprising a water-insoluble salt of a basic substituted aldimine of the formula type:

B B-(|J=NT in which B is selected from the class consisting of hydrogen atoms, hydroxy hydrocarbon and hydrocarbon radicals, and T is a non-aryl hydrocarbon radical; said aldimine salt being obtained from water-soluble, non-hydrophobe petroleum sulfonic acid of the green acid type.

3. A process for resolving petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier, comprising a water-insoluble salt of a basic substituted aldimine of the formula type:

H B(|J=NT in which B is selected from the class consisting of hydrogen atoms, hydroxy hydrocarbon and hydrogen radicals, and T is a non-aryl hydroxylated hydrocarbon radical; said aldimine salt being obtained from water-soluble, non-hydrophobe petroleum sulfonic acid of the green acid type.

4. A process for resolving petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier, comprising a water-insoluble salt of a basic substituted aldimine of the formula type:

in which 13 is selected from the class consisting of hydrogen atoms, hydroxy hydrocarbon and hydrocarbon radicals, and T is a non-aryl radical obtained by the acylation of a hydroxy hydrocarbon radical in which the acylating compound is derived from an acid containing not more than 32 carbon atoms; said aldimine salt being obtained from water-soluble, non-hydrophobe petroleum sulfonic acid of the green acid type.

MELVIN DE GROOTE. 

